//===-- RegAllocSimple.cpp - A simple generic register allocator ----------===//
-//
+//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+//
//===----------------------------------------------------------------------===//
//
// This file implements a simple register allocator. *Very* simple: It immediate
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/Compiler.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
+STATISTIC(NumStores, "Number of stores added");
+STATISTIC(NumLoads , "Number of loads added");
+
namespace {
- Statistic<> NumStores("ra-simple", "Number of stores added");
- Statistic<> NumLoads ("ra-simple", "Number of loads added");
+ static RegisterRegAlloc
+ simpleRegAlloc("simple", " simple register allocator",
+ createSimpleRegisterAllocator);
- class RegAllocSimple : public MachineFunctionPass {
+ class VISIBILITY_HIDDEN RegAllocSimple : public MachineFunctionPass {
+ public:
+ static char ID;
+ RegAllocSimple() : MachineFunctionPass((intptr_t)&ID) {}
+ private:
MachineFunction *MF;
const TargetMachine *TM;
const MRegisterInfo *RegInfo;
- bool *PhysRegsEverUsed;
-
+
// StackSlotForVirtReg - Maps SSA Regs => frame index on the stack where
// these values are spilled
std::map<unsigned, int> StackSlotForVirtReg;
void spillVirtReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned VirtReg, unsigned PhysReg);
};
-
+ char RegAllocSimple::ID = 0;
}
/// getStackSpaceFor - This allocates space for the specified virtual
/// register to be held on the stack.
int RegAllocSimple::getStackSpaceFor(unsigned VirtReg,
- const TargetRegisterClass *RC) {
+ const TargetRegisterClass *RC) {
// Find the location VirtReg would belong...
std::map<unsigned, int>::iterator I =
StackSlotForVirtReg.lower_bound(VirtReg);
// Allocate a new stack object for this spill location...
int FrameIdx = MF->getFrameInfo()->CreateStackObject(RC->getSize(),
RC->getAlignment());
-
+
// Assign the slot...
StackSlotForVirtReg.insert(I, std::make_pair(VirtReg, FrameIdx));
TargetRegisterClass::iterator RE = RC->allocation_order_end(*MF);
while (1) {
- unsigned regIdx = RegClassIdx[RC]++;
+ unsigned regIdx = RegClassIdx[RC]++;
assert(RI+regIdx != RE && "Not enough registers!");
unsigned PhysReg = *(RI+regIdx);
-
+
if (!RegsUsed[PhysReg]) {
- PhysRegsEverUsed[PhysReg] = true;
+ MF->setPhysRegUsed(PhysReg);
return PhysReg;
}
}
// Add move instruction(s)
++NumLoads;
- RegInfo->loadRegFromStackSlot(MBB, I, PhysReg, FrameIdx);
+ RegInfo->loadRegFromStackSlot(MBB, I, PhysReg, FrameIdx, RC);
return PhysReg;
}
// Add move instruction(s)
++NumStores;
- RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIdx);
+ RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIdx, RC);
}
std::map<unsigned, unsigned> Virt2PhysRegMap;
RegsUsed.resize(RegInfo->getNumRegs());
-
+
// This is a preliminary pass that will invalidate any registers that are
// used by the instruction (including implicit uses).
unsigned Opcode = MI->getOpcode();
const TargetInstrDescriptor &Desc = TM->getInstrInfo()->get(Opcode);
const unsigned *Regs;
- for (Regs = Desc.ImplicitUses; *Regs; ++Regs)
- RegsUsed[*Regs] = true;
-
- for (Regs = Desc.ImplicitDefs; *Regs; ++Regs) {
- RegsUsed[*Regs] = true;
- PhysRegsEverUsed[*Regs] = true;
+ if (Desc.ImplicitUses) {
+ for (Regs = Desc.ImplicitUses; *Regs; ++Regs)
+ RegsUsed[*Regs] = true;
+ }
+
+ if (Desc.ImplicitDefs) {
+ for (Regs = Desc.ImplicitDefs; *Regs; ++Regs) {
+ RegsUsed[*Regs] = true;
+ MF->setPhysRegUsed(*Regs);
+ }
}
-
+
// Loop over uses, move from memory into registers.
for (int i = MI->getNumOperands() - 1; i >= 0; --i) {
MachineOperand &op = MI->getOperand(i);
-
+
if (op.isRegister() && op.getReg() &&
MRegisterInfo::isVirtualRegister(op.getReg())) {
unsigned virtualReg = (unsigned) op.getReg();
- DEBUG(std::cerr << "op: " << op << "\n");
- DEBUG(std::cerr << "\t inst[" << i << "]: ";
- MI->print(std::cerr, TM));
-
+ DOUT << "op: " << op << "\n";
+ DOUT << "\t inst[" << i << "]: ";
+ DEBUG(MI->print(*cerr.stream(), TM));
+
// make sure the same virtual register maps to the same physical
// register in any given instruction
unsigned physReg = Virt2PhysRegMap[virtualReg];
if (physReg == 0) {
if (op.isDef()) {
- if (!TM->getInstrInfo()->isTwoAddrInstr(MI->getOpcode()) || i) {
+ int TiedOp = MI->getInstrDescriptor()->findTiedToSrcOperand(i);
+ if (TiedOp == -1) {
physReg = getFreeReg(virtualReg);
} else {
- // must be same register number as the first operand
- // This maps a = b + c into b += c, and saves b into a's spot
- assert(MI->getOperand(1).isRegister() &&
- MI->getOperand(1).getReg() &&
- MI->getOperand(1).isUse() &&
+ // must be same register number as the source operand that is
+ // tied to. This maps a = b + c into b = b + c, and saves b into
+ // a's spot.
+ assert(MI->getOperand(TiedOp).isRegister() &&
+ MI->getOperand(TiedOp).getReg() &&
+ MI->getOperand(TiedOp).isUse() &&
"Two address instruction invalid!");
- physReg = MI->getOperand(1).getReg();
- spillVirtReg(MBB, next(MI), virtualReg, physReg);
- MI->getOperand(1).setDef();
- MI->RemoveOperand(0);
- break; // This is the last operand to process
+ physReg = MI->getOperand(TiedOp).getReg();
}
spillVirtReg(MBB, next(MI), virtualReg, physReg);
} else {
Virt2PhysRegMap[virtualReg] = physReg;
}
}
- MI->SetMachineOperandReg(i, physReg);
- DEBUG(std::cerr << "virt: " << virtualReg <<
- ", phys: " << op.getReg() << "\n");
+ MI->getOperand(i).setReg(physReg);
+ DOUT << "virt: " << virtualReg << ", phys: " << op.getReg() << "\n";
}
}
RegClassIdx.clear();
/// runOnMachineFunction - Register allocate the whole function
///
bool RegAllocSimple::runOnMachineFunction(MachineFunction &Fn) {
- DEBUG(std::cerr << "Machine Function " << "\n");
+ DOUT << "Machine Function\n";
MF = &Fn;
TM = &MF->getTarget();
RegInfo = TM->getRegisterInfo();
- PhysRegsEverUsed = new bool[RegInfo->getNumRegs()];
- std::fill(PhysRegsEverUsed, PhysRegsEverUsed+RegInfo->getNumRegs(), false);
- Fn.setUsedPhysRegs(PhysRegsEverUsed);
-
// Loop over all of the basic blocks, eliminating virtual register references
for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
MBB != MBBe; ++MBB)
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